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Brachylophosaurus

Sternberg, 1953 bruh-KIL-uh-fuh-SOR-uhs or brak-i-LOH-fuh-SOR-uhs /brəˌkɪləfəˈsɔːrəs/

From Greek brachys meaning 'short', Greek lophos meaning 'crest', and Greek sauros meaning 'lizard'. Full meaning: 'short-crested lizard', referring to its reduced flat crest.

83.6–72.2 million years ago Campanian, Late Cretaceous
Late Cretaceous stages

Brachylophosaurus is a genus of hadrosaurid dinosaur that lived during the Late Cretaceous period of western North America. It was first named in 1953 by Charles Mortram Sternberg for a skull and skeleton Sternberg discovered in 1936 in the Oldman Formation of Alberta, Canada, naming the new taxon Brachylophosaurus canadensis for it. While this single specimen was the only known material of Brachylophosaurus for a long time, extensive discoveries in the Judith River Formation of Montana, USA have uncovered not only additional skulls and skeletons with extensive impressions of skin, but also a bonebed of 800 specimens. The earliest of these discoveries in Montana was named Brachylophosaurus goodwini by John R. Horner, but it is now believed that there was only a single species of Brachylophosaurus, with B. goodwini as either a junior synonym of B. canadensis or an indeterminate member of Brachylophosaurini.

Diagnosis

  1. Nasals developed into a paddle-like solid crest that extends caudodorsally and overhangs the dorsal region of the skull
  2. Nasals bearing an anteroposteriorly oriented groove that terminates in an elongated foramen medial to the prefrontal
  3. Prefrontal projected posteriorly, resting over the anterior process of the postorbital and extending ventromedially beneath the nasal
  4. Only the anterior sharp tip of the lacrimal contacts the maxilla
  5. Extremely elongated, rod-like anterodorsal process of the maxilla running medial to the narial cavity along most of the length of the external naris
  6. Forearm greatly elongated, with the radius and ulna longer than the humerus — unusual among flat-headed hadrosaurs

Species

Brachylophosaurus canadensis Sternberg, 1953

Type species

Named for Canada, where the holotype specimen was discovered in the Oldman Formation of Alberta.

Holotype
CMN 8893 , Canadian Museum of Nature
Material
Skull, cervical and anterior dorsal vertebrae and ribs, scapulae, coracoids, humeri, left ulna, and radius
Horizon
Oldman Formation, Campanian, Late Cretaceous , 83.6–72.2 million years ago
Locality
Little Sandhill Creek, near Steveville, Alberta, Canada Sternberg (1953) gives quarry No. 58, "60 feet above the level of Red Deer River". Cuthbertson and Holmes (2010) place the type locality "7.5 m below the Dinosaur Park Formation-Oldman Formation contact", on a personal communication from David Evans.

Notable specimens

  • “Elvis”

    MOR 794 Museum of the Rockies Found 1994 by Nate Murphy most complete

    Articulated skeleton and skull preserved in three dimensions without flattening, missing only the very tip of the tail, making it about 95% complete. Its completeness enabled Prieto-Márquez's 2005 redescription of the genus. On display at the Phillips County Museum.

    Prieto-Márquez (2005)

  • FMNH PR 862

    Field Museum of Natural History Found 1922 by George Fryer Sternberg historic

    Disarticulated crested-hadrosaur skull collected September 9, 1922 on the Field Museum's Red Deer River expedition under Elmer S. Riggs. Recognized in field notes as an entirely new type of crested hadrosaur, it was later referred to Brachylophosaurus, predating the genus's naming.

    Brinkman (2013)

  • TMP 1990.104.0001

    Royal Tyrrell Museum of Paleontology gut contents

    Well-preserved southern Alberta specimen from near Manyberries and Onefour, preserving the front half of a skeleton and a complete skull. Remains largely undescribed apart from comparison of its stomach contents and skeleton to the holotype.

    Cuthbertson & Holmes (2010)

  • “Leonardo”

    JRF 115 Great Plains Dinosaur Museum Found 2000 exceptional preservation

    Mummified specimen with about 90% of its cast surface covered by skin impressions, recognized by Guinness World Records as the Best Preserved Dinosaur. Preserves polygonal scales, a dorsal row of triangular feature scales, stomach contents, and needle-like parasitic worms.

    Murphy et al. (2007)

References

  1. Sternberg, C. M. (1953). A new hadrosaur from the Oldman Formation of Alberta: discussion of nomenclature. National Museum of Canada Bulletin 128: 275-286. sternberg1953a
  2. Prieto-Márquez, A. (2005). New information on the cranium of Brachylophosaurus, with a revision of its phylogenetic position. Journal of Vertebrate Paleontology 25(1): 144-156. doi:10.1671/0272-4634(2005)025[0144:NIOTCO]2.0.CO;2 prieto-márquez2005a
  3. Murphy, N. L.; Trexler, D.; Thompson, M. (2007). "Leonardo," a mummified Brachylophosaurus from the Judith River Formation. Horns and Beaks: Ceratopsian and Ornithopod Dinosaurs 117-133. Indiana University Press, Bloomington.

    Describes Leonardo, a mummy preserving a dorsal soft-tissue frill that continues onto the proximal tail.

    murphy2007a
  4. Cuthbertson, R. S.; Holmes, R. B. (2010). The first complete description of the holotype of Brachylophosaurus canadensis Sternberg, 1953 (Dinosauria: Hadrosauridae) with comments on intraspecific variation. Zoological Journal of the Linnean Society 159(2): 373-397. doi:10.1111/j.1096-3642.2009.00612.x cuthbertson2010a
  5. Brinkman, P. D. (2013). Red Deer River Shakedown: A history of the Captain Marshall Field Paleontological Expedition to Alberta, 1922, and its aftermath. Earth Sciences History 32(2): 204-234. doi:10.17704/eshi.32.2.n450m52t2964730k brinkman2013a
  6. Paul, G. S. (2024). The Princeton Field Guide to Dinosaurs (3rd ed.). Princeton University Press.

    Source of the appearance features.

    paul2024a